Scaffolding winch with motor

ABSTRACT

A scaffolding motor winch with a safety device to prevent a falling of the scaffolding platform. The safety device control means are coupled to the motor control means for lowering the platform to lock or unlock the safety device only when the motor is stopped.

United States Patent Marcel Durand Grenoble, France 22,220

Mar; 24, 1970 June 22, 1971 Jun Polnagalski S.A. Famine, France Apr. 23,1969 France Inventor Appl. No. Filed Patented Assignee PrioritySCAFFOLDING WINCH WITH MOTOR 7 Claims, 5 Drawing Figs.

US. Cl. 182/112, 182/142 Int. Cl. E04g 3/10 50 Field of Search 182/112,141,142,143,147

[56] References Cited UNITED STATES PATENTS 2,662,734 12/ 1 953Allenbaugh 182/1 12 2,939,550 6/1960 Puttre 182/112 3,021,918 2/1962Medawar.... 182/112 3,386,530 6/1968 Thompson 182/112 PrimaryExaminerReinaldo P. Machado ArtorneyStevens, Davis, Miller & MosherABSTRACT: A scaffolding motor winch with a safety device to prevent afalling of the scaffolding platform. The safety device control means arecoupled to the motor control means for lowering the platform to lock orunlock the safety device only when the motor is stopped.

SHEET 1 OF 3 PATENTEU JUN22 I971 PATENTED M22197! SHEET 2 OF 3 PIE 2SCAFFOLDING WINCH WITH MOTOR The invention relates to an apparatus forthe raising and lowering of a gangway or a scaffolding platform,comprising at least a winch secured to the platform and operated by amotor and locking means capable of gripping a safety cable, to stop thedescent and hold the said platform.

An object of the present invention is to provide a winch apparatushaving perfect safety in operation and excluding any possibility of afalse maneuver.

According to the invention the lowering procedure is obligatorilypreceded by the unlocking of the safety device, in such manner as toprevent the latter, on entering into action, from wedging on the cableand holding the platform. In the latter case the safety device wouldcarry the load while the support cable slackens and the operator mustinitiate a lifting maneuver, this taking the load off the safety device,before he is able to unlock it.

According to the invention the unlocking control means are coupled tothe motor control means for lowering the platform so as the safetysystem is actioned to lock or unlock only when the motor is stopped andcannot therefore intervene and lock during normal operation.

The safety device control may be coupled in an analogous manner to the.control used for lifting, but according to a development of theinvention the said locking means include a brake device with shoescapable of gripping the said cable and so arranged as to induce aself-gripping of the brake in the downwards direction and automaticrelease in the upward direction.

The motorized drive shows a great advantage in that it does not need anoperator for each winch on the platform, and it would be tiresome tohave to use several operators just to operate the motors. According tothe invention a central control for lowering operates from a distancethe control means of the locking means of the various winches whichaction on reaching their limits of travel the motor control means of theassociated winches.

Other advantages and objects will become more readily apparent from thefollowing description of an embodiment of the invention represented inthe annexed drawings in which:

FIG. 1 represents diagrammatically a scaffolding platform equipped witha safety device according to the invention;

FIG. 2 is a view in elevation, on an enlarged scale, of a winch and theassociated means of locking according to FIG.

FIG. 3 shows in section and in plan the means of locking;

FIG. 4 is a view in elevation illustrating the means of locking and themotor of the winch;

FIG. 5 is a view analogous with that of H6. 4 of a variant in design.

On the drawings a scaffolding platform is supported by two liftingwinches 12 and 14, each acting in conjunction with a support cable 16respectively 18. Winches 12, 14 are advantageously of the type using agrooved pulley which are the object of French Pat. No. 1,531,386, andfor reasons of clarity of the disclosure, only one of them, winch 12will be summarily described hereafter.

Cable 16 is lodged in the V-shaped groove of a hauling pulley 20 whichit embraces over part of its circumference. A compression wheel 22,fitted on an articulated lever 24, presses cable 16 into the groove ofpulley 20 under pressure derived from the tractive stress exerted oncable 16 by a wheel 26 carried by lever 24 and engaging cable 16. Thehauling pulley 20 is driven in rotation, through the intermediary of aworm-drive reducer (not shown), by a motor 28, electric for instance,which may operate in two directions. A contactor 30 with pushbuttons 32and 34 for starting motor 28 in one direction or the other controls therotation movement of hauling pulley 20 either in the direction in whichplatform 10 is raised, or in the direction in which it is lowered (seeFIG. 4). With each winch, 12 and 14 is associated a safety system 36respectively 38 each of which acts on a safety cable or rod 40 whichextends over the whole lifting height and is kept taut, by a weight 44,for example. The safety systems 36 and 38 are mounted on the side plateof the winch 12 respectively 14. The safety system 36 or 38, one ofwhich only will be described, the other being identical, has two jaws46, 48, between which is inserted cable 40 which can be wedged by theclamping ofjaws 46, 48. Jaw 46, in the form of a U enclosing cable 40and jaw 48, are articulated at 52 and 52' on two locking rods 50 and 50,the opposite end of each rod being fitted so as to pivot on a fixed axle54 respectively 54' on the frame of winch 12. The ends of the lockingrods 50 and 50 articulated respectively at 52 and 52 are in the form ofa cam or an eccentric 56 and 56' coacting with jaw 48 in such a mannerthat a limited movement upwards of jaws 46, 48 in the direction of arrowF on the drawings results in a limited pivoting of rods 50 and 50' inthe trigonometric direction (arrow F,) and therefor in a closing of jaws46, 48. A movement downwards in the opposite direction provokes theopening of jaws 46, 48. A spring 58 permanently exerts an upwardpressure on jaws 46, 48 which are consequently applied against cable 40.It is easily understood that the slightest relative movement of cable 40in the direction of arrow F in relation to frame 12 tends to draw jaws46, 48 upwards by friction and thus to close them together so that theylock on cable 40.

Rod 50 is rigidly connected to an operating lever 60 which may rotate onaxle 54. By a rotation movement of lever 60 in the direction opposed tothat of arrow F shown on the drawings, and against the pressure exertedby spring 58, the opening of jaws 46, 48 is brought about by thepivoting of rods 50, 50' in the manner described above. At the end ofits travel while opening the jaws the end of lever 60 butts againstpushbutton 34 which is pushed in and starts the motor in the directionin which the platform 10 is lowered. inversely, when lever 60 isreleased button 34 is freed, motor 28 is stopped and spring 58 bringsthe locking system into its normal position in which the jaws 46, 48,are applied to cable 40. Timing of the return of lever 60 may introducedby means of some device (not shown) so as to permit the completestopping of the motor before the closing of jaws 46, 48.

The functioning of the device according to the invention is obvious:

To raise the platform 10 pressure is applied to buttons 32 controllingthe lifting by winches 12 and 14, which by the rotation of the haulingpulleys hoist themselves up along the support cables 16 and 18. Lockingsystems 36, 38 open automatically by virtue of the relative movement ofaxles 54, 54' in relation to cables 40, 42 and in no way impede theascent. When motors 28 are stopped by releasing buttons 32, spring 58closes once more jaws 46, 48 to prevent a falling of the platform.

The lowering of platform 10 is effected by the actioning of levers 60 ofwinches 12 and 14 which in a first phase of the pivoting movement in aclockwise direction open jaws 46, 48 so as to free cables 40, 42 and ina final phase action pushbuttons 34 controlling the motors 28 for thedescent. On releasing levers 60 buttons 34 are freed and stop motors 28and in a second phase, preferably timed, spring 58 closes once morelocking jaws 46, 48. it is easily seen that any false move isimpossible, as the sequences of control must necessarily be respected.On the other hand a falling of the load is always prevented by thesafety device.

The use of a plurality of winches 12 on the same platform 10 implies thesimultaneous operation of spaced devices, and thus the presence ofseveral operators. FIG. 5 shows an embodiment according to the inventionpermitting remote control from a single post 62 located for example inthe center of the platform 10 (see FIG. 1). Pushbuttons 32 for movementupwards operate directly winches 12 and 14 while lowering buttons 64excite electromagnets 66 with plunger pistons 68 associated with eachwinch 12, 14 which action the various operating levers 60. When plunger68 reaches its limit of travel and jaws 46, 48 are thus opened, theclosing ofa contact 70 causes the starting of motor 28. The functioningis moreover identical with that described above.

The invention is of course in no way limited to the applications mostparticularly described and shown as examples in the attached drawings.

What I claim is:

I. An apparatus for raising and lowering a scaffolding platformcomprising at least one winch secured to said platform and driven by amotor so as to raise or lower the platform, locking means that can gripa cable extending along the travel path to stop the descent and holdsaid platform, control means which controls the unlocking of saidlocking means, control means which controls said motor in the directionfor lowering said platfonn, coupling means to couple said unlockingcontrol means and said motor control means in such a manner that thelatter is necessarily actioned, to engage a lowering movement, afterunlocking of said locking means and to stop the said lowering movementbefore the locking of said locking means.

2. An apparatus according to claim 1, wherein said locking meanscomprise a brake device with jaws capable of gripping the said cable andso arranged as to induce an autoclamping of the said brake in thedirection of lowering of the platform and automatic release in theupward direction.

3. An apparatus according to claim 2. wherein said unlocking controlmeans engage and operate at the limit of its control movement said motorcontrol means in the direction of descent of the platform.

4. An apparatus according to claim 3, in which the said brake with jawshas two rods articulated at one end on the frame of the said winch andthe other end of which coacts with the said jaws to induce their closingor opening when pivoted by an operating lever.

5. An apparatus according to claim 1, wherein the winch is driven by anelectric motor with pushbuttons controlling the raising and lowering ofthe load, the operation of the said pushbutton for lowering beingeffected by a continued movement of the said unlocking control means ofsaid locking means.

6. An apparatus according to claim 5, which comprises a plurality ofsupporting winches and a common control device which remotely controlsall said unlocking control means of the various winches, which onreaching their limit of travel operate the control means of the saidmotors of the associated winches.

7. An installation for raising and lowering a scaffolding platformincluding at least one cable supporting the platform, a winch secured tosaid platform and having a grooved pulley in which is housed the saidsupport cable and the rotation of which causes the raising or loweringof the platform up or down the said support cable, an electric motordriving the said winch in the raising or lowering directions, a safetydevice which automatically cancels a downward movement of platform, andwhich may be unlocked, a component operating the unlocking of the saidsafety device, a control component for the said electric motor to causeits operation in the downward direction and a device coupling the saidoperating components causing the unlocking of the safety device beforethe operation of the lowering control of the said motor and a controlfor stopping the descent before the locking of the said safety device.

1. An apparatus for raising and lowering a scaffolding platformcomprising at least one winch secured to said platform and driven by amotor so as to raise or lower the platform, locking means that can gripa cable extending along the travel path to stop the descent and holdsaid platform, control means which controls the unlocking of saidlocking means, control means which controls said motor in the directionfor lowering said platform, coupling means to couple said unlockingcontrol means and said motor control means in such a manner that thelatter is necessarily actioned, to engage a lowering movement, afterunlocking of said locking means and to stop the said lowering movementbefore the locking of said locking means.
 2. An apparatus according toclaim 1, wherein said locking means comprise a brake device with jawscapable of gripping the said cable and so arranged as to induce anautoclamping of the said brake in the direction of lowering of theplatform and automatic release in the upward direction.
 3. An apparatusaccording to claim 2, wherein said unlocking control means engage andoperate at the limit of its control movement said motor control means inthe direction of descent of the platform.
 4. An apparatus according toclaim 3, in which the said brake with jaws has two rods articulated atone end on the frame of the said winch and the other end of which coactswith the said jaws to induce their closing or opening when pivoted by anoperating lever.
 5. An apparatus according to claim 1, wherein the winchis driven by an electric motor with pushbuttons controlling the raisingand lowering of the load, the operation of the said pushbutton forlowering being effected by a continued movement of the said unlockingcontrol means of said locking means.
 6. An apparatus according to claim5, which comprises a plurality of supporting winches and a commoncontrol device which remotely controls all said unlocking control meansof the various winches, which on reaching their limit of travel operatethe control means of the said motors of the associated winches.
 7. Aninstallation for raising and lowering a scaffolding platform includingat least one cable supporting the platform, a winch secured to saidplatform and having a grooved pulley in which is housed the said supportcable and the rotation of which causes the raising or lowering of theplatform up or down the said support cable, an electric motor drivingthe said winch in the raising or lowering directions, a safety devicewhich automatically cancels a downward movement of platform, and whichmay be unlocked, a component operating the unlocking of the said safetydevice, a control component for the said electric motor to cause itsoperation in the downward direction and a device coupling the saidoperating components causing the unlocking of the safety device beforethe operation of the lowering control of the said motor and a controlfor stopping the descent before the locking of the said safety device.